[thebiss]

Under my desk right now is a too-underutilized-to-upgrade-NAS that has been spinning 1TB Western Digitals since 2010. Between RAID-Z2 and cloud backups, there's almost no reason to get rid of them except for performance, which doesn't matter here.

[toast0]

If all of your disks are about the same age, from the same vendor, it might be reasonable to replace them over time to mitigate the risk that a firmware or manufacturing issue results in them all failing around the same time. Many vendors have had firmware errors where counters rolled over and the drive becomes inaccessible (generally much sooner than 13 years though).